220 M³/Min Centrifugal Vacuum Pump Low Energy Consumption PLC Control

Product Specification

220 m³/min Turbo Vacuum Pump System For Paper Machines

Introduction

Turbine fan is a kind of special centrifugal fan, which is generally divided into multi-stage closed centrifugal fan and single-stage open centrifugal fan. They use the multi-stage impeller installed in the shell and diffusion system to form vacuum. With the rotation of the impeller, air enters the hole in the middle of the impeller, and is accelerated and pressurized in the process of radial outward movement. Then the second stage impeller accelerates the air from the first stage, and then to the third stage and the fourth stage, so as to generate vacuum. The air is inhaled from different levels, thus producing different vacuum degrees to meet the needs of the paper machine vacuum system. As shown in Figure 1 is a simple schematic diagram of a multistage turbine.

No matter multi-stage closed fan or single-stage open fan is used as vacuum pump, it has the characteristics of large suction and stable vacuum level. However, when the vacuum is high and the amount of air available for suction is less and less, air reflux and surge often occur. At this time, the heated air after being accelerated flows back to the suction port, and the intake pipe will be heated, which will seriously damage the stability of the vacuum degree. Therefore, the inlet of each turbine is equipped with anti surge valve. When the vacuum degree is high and the suction capacity is insufficient, the anti surge valve will automatically open according to the effective power of the turbine, and increase the air flow to prevent the occurrence of surge, so as to make the equipment power consumption and the required vacuum degree stable.

Process Flow Diagram of Using the Turbine

Generally, a multistage turbine and two single-stage turbines are used in parallel. Each part of the paper machine that needs the same vacuum degree is connected to one or more concrete gas-water separation tanks. Figure 2 is the basic process flow diagram of using the turbine.

Application description

The suction capacity of the turbine is large. Generally, multiple points with similar vacuum requirements can be used together. When it is used as a vacuum equipment, it has the characteristics of centralized equipment, high efficiency and low energy consumption.Taking a 400 Thousand tons paper machine as an example, only three turbines are needed, the total installed power is 6550kw, and its vacuum capacity is equivalent to the requirement of 15 sets of water ring vacuum pumps with installed power of 8810kw, but the installed capacity is reduced by 2260kw. Under the same circumstances, it can save about 25% energy than the ordinary water ring vacuum pumps; after the air is rapidly heated and compressed by the turbine, the temperature of the discharged air is as high as 120-180 ℃, and the remaining heat is usually used for heating the white water and air system of the paper machine through the heat exchanger.The turbine does not need water as the medium when it works, and the annual consumption of water for the water ring vacuum pump is about 300000 tons per year. A single-stage turbine is designed with 24 deflectors on the shell outside the impeller, which can adjust the flow rate of air through the turbine, so as to adjust the vacuum degree.

Use notice

When the turbine is used in the vacuum system, its operating speed is higher. The operating speed of the multi-stage machine is generally 5000r / min, and that of the single-stage machine is more than 10000r / min. Therefore, the whole equipment needs a heavy foundation with high quality to prevent high frequency vibration.

Due to the large power of a single device, the load fluctuation of the system grid will be caused when the device is started or stopped. Before each start, the motor protection program will check whether the shutdown time is enough for a specified time interval. The impeller speed of the turbine is very high, so the machining and installation accuracy of the equipment is required to be improved accordingly, and the high-precision dynamic balance test of the impeller is required at high speed. In order to prevent moisture or foreign matters from entering, a large-scale concrete air-water separation tank must be set up. Stainless steel plate is used for partition inside the separation tank, the maximum wind speed shall not exceed 3m / s.

After the machine is installed, it is necessary to thoroughly clean the pipeline to prevent foreign matters from remaining in the pipeline and damaging the equipment.

Advantages of centrifugal vacuum pump compared with water ring vacuum pump

Centrifugal vacuum pump works without water and achieve suction sealing by itself, therefore, the water and the electricity in the water supply system are both saved. See below chart.

While water ring vacuum pump has the following natural defects

When the blade is in direct contact with white water, there is cavitation problem in the blade, white water impurities cause equipment scaling, reduce suction capacity, and increase energy consumption, white water impurities are also easy to cause rotor and pump body lock, bearing, shaft head wear and other problems which lead to high failure rate of equipment, frequent maintenance, high maintenance cost and short service life. Below chart indicates that the performance of water ring vacuum pump decreases with the service life increasing. The impeller wear increases leakage, decreases vacuum and reduces efficiency.

Aviation Engine Blade Manufacturing Process

• The machining precision and manufacturing level of impeller blades are important factors that affect engine performance, safety and life.
• There are strict requirements for the manufacturing accuracy of blades in the aviation industry, which must have precise size, accurate shape and strict surface integrity.

Parameters of High-Speed VF Centrifugal Vacuum Pump